1. Field of the Invention
The present invention relates to a surfactant composition for agricultural chemicals, which is suitably used as an emulsifier, dispersing agent, spreading agent, functional spreading agent (adjuvant), and water dispersible agent for agricultural chemicals.
2. Description of the Related Art
In order to allow agricultural chemicals to sufficiently exhibit their effects, formulations of agricultural chemicals, such as bactericides, insecticides, acaricides, weed-killers, and plant growth regulators, are suitably selected considering efficiency for spraying an agricultural chemical for use, safety thereof, or the like. Among such formulations, an emulsified dispersion liquid of an agricultural chemical is expected to be entirely and uniformly deposit on the target for spraying, and has been used in the art. In order to disperse an agricultural chemical, which is generally an oily substance, in water, various surfactants have been used in the emulsified dispersion liquid of the agricultural chemical.
Surfaces of leaves or stems of plants and surfaces of insects have a substance or structure which repels of liquids, or prevents from being wet by liquids. For example, on surfaces of plants, wax-lipoids are secreted, or feathery fibers are closely grown. In another case, fine irregularities are present on surfaces of plants. Moreover, a layer similar to a keratin is present on surfaces of pest insects. All of these materials have such qualities as to repel an aqueous dispersion liquid of agricultural chemicals. Due to this, there are cases where the sprayed agricultural chemical may not provide a sufficient effect thereof. Therefore, spreading agents and functional spreading agents (adjuvants) are used in agricultural chemicals for providing agricultural chemicals with enhanced qualities such as wetting ability, permeability, spreading, and fixing, to thereby increase chemical effects of the agricultural chemicals.
Conventionally, as these surfactants for agricultural chemicals, nonionic surfactants of various alkyl oxide adducts have been known. For example, a spreading agent for agricultural chemicals, which contains a nonionic ester surfactant formed of specific fatty acid polyoxyalkylene alkyl ether, is disclosed in Japanese Patent Application Laid-Open (JP-A) No. 06-329503. An agrochemical spreader composition, which is a surfactant composition excellent in low-temperature stability is disclosed in JP-A No. 2001-288006.
A surfactant for agricultural chemicals formed of a nonionic surfactant is generally used for formulating a fluid agricultural chemical, or is commonly added to a fluid preparation of an agricultural chemical as a fluid spreading agent for an agricultural chemical. Therefore, in actual practices, such surfactant is required to have basic performances such as solubility for dissolving an oil-soluble agricultural chemical component; low foamability and defoamability for improving handling at the time of preformulation in a tank and at the time of spraying, and preventing foaming (polluting) in rivers or the like; and permeability to surfaces of plants and the like, as well as stability which prevents precipitation or separation of substances at the time of use, during storage at low temperature, or when the temperature is changed from low temperature to normal temperature.